How do I compile a .cpp source file into a .dll?
There are two steps you need to follow in order to compile a dll:
Here is one example using gcc:
gcc -c source.cpp //compile sources; will output "source.o"
gcc -shared -o mydll.dll source.o //add -shared to create a dll, will output "mydll.dll"
You have to compile cpp files into .obj files, then link them to produce a .dll.
A dll file is a library file, which is composed of many object files. This means you need to compile your .cpp file then combine it with any other files you need into the .dll.
Here's a tutorial I found with a quick google: http://www.icynorth.com/development/createdlltutorial.html
EDIT A fix for the above link since it's dead now https://web.archive.org/web/20130924001807/http://icynorth.com/development/createdlltutorial.html